DE10151118A1 - Process for transferring raw data and field device - Google Patents

Abstract

The invention relates to a method for transmitting raw data (36) between a field device (33) and a user device (30) for observation and/or operation of said field device (33), in addition to the embodiment of said field device (33). The raw data (36) is pre-held in the field device (33). A server device (34) is embodied in the field device (33). A browser device (31) is installed onto the user device (30) for data communication with the server device (34). The inventive method comprises the following steps: a communication link is set up in order to transmit electronic data between the field device (33) and the user device (30); an electronic description page (35) which can be graphically outputted on the user device (30) is transmitted with the aid of the browser device (31) from the server device (34) of the field device (33) to the user device (30) via said communication link whereby the electronic description page (35) consists of at least one electronic reference to the raw data (36) which is pre-held in the field device (33); the raw data (36) is transmitted from the field device (3 ) to the user device (33) and the raw data (36) is automatically processed (36) in the user device (30).

Description

The invention is in the field of remote controlled Operating, in particular for observing and operating, Field devices.

Field devices are used in the automation of various technical processes used, for example Monitoring a production or manufacturing process or of a processing process. With field devices, it can the production facilities themselves or devices for Monitor, preferably to control and / or regulate in Dependency on recorded field data, the used trade technical means of production or systems.

When operating the field devices fall into the field devices Raw data that can be processed further, for example for evaluating measurement processes or for error detection. With the help of different technologies, the Field devices in particular recorded measurement data that can be buffered and / or processed further. About that In addition, the raw data available in the field device Information about device-specific parameters includes how predefined and / or changeable settings of the Field device. This raw data can include measured values, Event lists, diagnostic data, error messages or fault records be in a binary format internal to the field device.

One is for the evaluation of the raw data by the operating personnel Visualization / presentation of the raw data necessary. in this connection can basically between processing the raw data in the field device itself and a transfer of the raw data distinguished from an observation and operating device be that can be connected to the field device.

The transfer of raw data to the observation and Control device has the advantage of a higher one Ease of use, as this is usually very low on the field devices is; there are only simple operating actions for Evaluation / processing of raw data possible on the field device. About that In addition, there is a graphic display of the Raw data often cannot be executed. So it got complex Operating programs for remote control of the field devices proposed. However, when using these programs arises a very high effort if standardized Communication mechanisms should be used. Generally, they require known operating technologies of telecontrol technology, for example the use of a WIN-CC operator station for operation of field devices, attention to the technical peculiarities of the individual field devices.

The object of the invention is an improved possibility to transfer raw data from field devices to create the essentially independent of the specific Field device training is and therefore high compatibility guaranteed.

The object is achieved by the method according to claim 1 and solved the device according to claim 11.

A major advantage over the invention the prior art is that the raw data generated in the field device by means of use of a browser that is based on standard Communication technologies based and therefore not by the specific training of the field device depends. The proposed way of transferring the raw data allows it basically the raw data with a standard browser a standard personal computer to retrieve the raw data then processed with application programs. For the Execution is in the standard used by the user Personal computer or the like is sufficient Computer power available that is not available in the field device. This also applies to those required by the application program Storage space, which is usually also not in the field device is available.

An expedient development of the invention provides that the electronic description page after transmission the user device automatically in the user device is analyzed to get the reference to the raw data capture, and that the raw data after capturing the reference in the electronic description page automatically from the Field device are transmitted to the user device. This enables the raw data to be transferred from the field device to the User device can be loaded without the user intervening got to.

To give the user of the user device the choice between different raw data sets in a simple way allow, a preferred embodiment of the invention provides that one of the reference in the electronic Description assignable selection by a user using a Selection means of electronically in the user device is recorded and that the raw data after recording the Selection of the user automatically from the field device to the User device are transmitted.

The described retrieval of the raw data can be done with With the help of an expansion module ("plug-in" module) for the Browser setup. This version can be used for the retrieval of static data change only over longer periods of time or only occur sporadically. The TCP protocol is advantageous here used. Execution with the help of an ActiveX Component would be possible. On the other hand, for the retrieval of dynamic data that changes continuously, for example event lists and / or measured values, a client process in the browser setup can be used, in which case preferably an RPC protocol standard can be used.

The method can be used in conjunction with the widespread Standard technology HTTP (HTTP - "Hypertext Transfer Protocol ") are used when the electronic Description page is expediently an HTML page.

One regarding the optimized use of Data connections preferred development of the invention provides that the raw data from the field device to the user device the communication link are transmitted.

To the efficiency of the transmission of various data formats to improve, an advantageous embodiment of the Invention provide that to transmit the electronic Description page and for transferring the raw data different protocols can be used. This makes it possible choose a suitable transmission protocol.

A preferred development of the invention provides that the browser device from the field device to the User equipment transmitted raw data analyzed and that to Processing the raw data in the user device Application program depending on the result of the analysis the raw data is started automatically. This will ensures that the raw data automatically matches the intended application program are processed. At the The raw data can be analyzed, for example File extension or its MIME type (MIME - "Multipurpose Internet Mail Extension ") as an indication of what is to be called Application program can be evaluated.

According to a further aspect of the invention is a field device with a connection for a communication link that from a client device via an IP address is addressable, a server device for data communication with a browser installed on the client device Establishment via the connection and a storage facility with an electronic stored therein Description page created, being the electronic description page an electronic reference to those held in the field device Includes raw data and being electronic Description page, including the one using the electronic reference referenced raw data, via the server device and the Connection is electronically available. The raw data from the Field devices can be accessed using a standard browser become. There is no need specific to the field device coordinated operating program, which is particularly advantageous if the operating system or based on it Operating programs must be updated.

The devices according to the dependent device claims assign the in connection with the associated Process claims listed advantages accordingly.

The method and / or the device can advantageously be used for Monitoring energy systems are used.

The method and / or the device can advantageously be used for Monitoring energy systems are used.

The invention is based on Embodiments explained with reference to a drawing. Here show:

Figure 1 is a schematic representation with a device network and a company intranet, which are connected via a proxy server.

Figure 2 shows a surface configuration of a browser device with graphical representations for a plurality of field devices.

Fig. 3 is a different surface configuration of the browser device with a graphical representation of a front view of a field device;

Fig. 4 is a schematic representation of a field unit and a user's personal computer;

Figure 5 is a flow chart for downloading of HTML pages as part of a monitoring and control system.

Fig. 6 is a block diagram for explaining an RPC call;

FIG. 7 shows the arrangement with the device network and the company intranet according to FIG. 1, individual elements of the proxy server being shown schematically;

Fig. 8 is a schematic block diagram of the proxy server;

9 is a schematic diagram illustrating a client / server interaction.

Fig. 10 is a schematic view showing a device identification in a master / slave arrangement;

FIG. 11 is a Nassi-Sneider diagram;

Fig. 12 is a schematic tree diagram of a method of device discovery;

FIG. 13 is a schematic illustration of a master / slave arrangement for explaining a configuration query;

FIG. 14 is a schematic block diagram of a device management in the proxy server;

Figure 15 is a schematic block diagram for explaining the functional integration of an XSL parser in the proxy server (XSL - "Extended Stylesheet Language");. and

Fig. 16 is a schematic block diagram for explaining an XSLT processor (XSLT - "Extended Stylesheet Language Transformations").

The following is a usable in connection with field devices so-called observation and operating system (BuB system) described.

Fig. 1 shows a schematic architecture of two networks, a network device having a plurality of field devices FG1. , .FGN and a company intranet with several user facilities N1. , .NN, preferably personal computer (PC). The device network and the company intranet are connected via a proxy server 1 . The proxy server 1 is part of the observation and operating system and serves as a gateway between the device network and the company intranet. With the help of the BuB system, information, for example measurement and / or status data, is obtained from the field devices FG1. , .FGN recorded and sent to user facilities N1. , .NN transmitted to a user of the user devices N1. , .NN about the operating status of the field devices FG1. , To inform .FGN. On the other hand, the BuB system is used to record operator input or control inputs with the help of the user devices N1. , .NN and to convert the inputs of the user in the field devices FG1. , .FGN. With the field devices FG1. , .FGN can be any device for observing, measuring, controlling and / or regulating a wide variety of physical quantities in different technical processes, for example for monitoring and / or controlling energy technology systems, for example a substation.

The device network comprises individual PPP connections 2 (PPP - "Point to Point Protocol"), which can be connected to the proxy server 1 via a star coupler 3 , or a separate Ethernet segment. The proxy server 1 provides its own homepage in the form of HTML data (HTML - "HyperText Markup Language"), which provides an overview of the field devices FG1 that can be reached in the device network. , .FGN shows (see Fig. 2); the homepage can be accessed using a standard browser in the user facilities N1. , .NN can be displayed.

Referring to FIG. 1, the field devices FG1. , .FGN only equipped with the star coupler 3 and a modem 4 connected to it. In this case, the field devices are FG1. , .FGN connected via an asynchronous serial interface directly to the modem 4 via the star coupler 3 . Different forms of coupling via active and passive star couplers are possible. As a protocol for access to the field devices FG1. , .FGN uses an IP protocol (IP - "Internet Protocol") over a PPP link layer.

If the field devices FG1. , .FGN are equipped with an Ethernet connection, the Ethernet connections are connected to a switch or a hub. If this switch or hub has a PPP port in addition to Ethernet ports, then this is called a router. This PPP port can then also be connected directly to the modem 4 .

The user devices connected to the local network have N1 on the company intranet. , .NN access to a modem 5 , which can be connected to the modem 4 of the device network via a telecommunications network 6 , for example a telephone network based on an ISDN or a cellular network. Is in the user facilities N1. , .NN each set up a dial-up connection (remote data transmission), can be set up by the user equipment N1. , .NN each have access to the field devices FG1. , .FGN done. If the proxy server 1 is now used by the user devices N1. , .NN can be accessed by any of the user devices N1 connected to the company intranet. , .NN to the field devices FG1. , .FGN can be accessed for monitoring and operation. The proxy server 1 "mirrors" all field devices FG1. , .FGN, ie information about the field devices FG1. , .FGN, on the company intranet. For this purpose, the following protocols are processed by proxy server 1 : HTTP protocol (HTTP - "Hypertext Transfer Protocol" and RPC protocol (RPC - "Remote Procedure Call"). The HTTP protocol is used for the transmission of static data. These are Data that are transmitted only once to the proxy server 1 and are then stored there in a file memory for later retrieval by the user devices N1 ... .NN The RPC protocol, which is also an IP-based protocol, is used to transmit dynamic data The dynamic data are, in particular, measured values and / or event lists recorded in the field devices FG1. .FGN, relating to information about events in the field devices FG1. .FGN.

The HTTP protocol allows the user devices N1. , .NN access to the field devices FG1. , .FGN. When accessing the BuB system, HTML data is first transmitted from the field device to the user device used in this application by selecting the associated IP address of the field device to be operated / observed, the HTML data comprising data with the A representation of the field device can be generated in the browser device of the retrieving user device, as is shown by way of example in FIG. 3. The retrieval of the HTML data for generating the representation according to FIG. 3 can be triggered by the user using a selection of one of the field devices shown in the overview in FIG. 2, for example by actuating a mouse or a keyboard of the user device.

According to FIG. 3, the following information is shown on the surface 20 of the browser device (cf. left-hand side in FIG. 3): field device family (eg SIPROTEC4), field device type and field device type 21 , an operating tree 22 , the version of the BuB -Tools 23 (version and date) and details of connection 24 with the field device (MLFB - "machine-readable manufacturing designation", BF number, connection status and IP address). The HTML page 25 assigned to a link or branch in the operating tree 22 is also displayed on the surface. Depending on the link selected in the operating tree 22 , the associated HTML page 25 is displayed on the surface 20 of the browser device.

The field devices FG1. , .FGN stored HTML pages, ie also the HTML page 25 used to generate the representation shown in FIG. 3, can include Java code that the browser device of the respective user device N1. , .NN causes parallel to the existing HTTP connection to display the field devices FG1. , .FGN loaded HTML page another connection with the field devices FG1. , .FGN to build. This second connection uses the RPC protocol to get dynamic data, such as event lists or measured values, from the field devices FG1. , .FGN particularly quickly and effectively for the display in the user facilities N1. , .NN to be transmitted within a selected HTML page, for example the HTML page 25 shown in FIG. 3.

Information retrieval from the field devices

FIG. 4 shows a schematic illustration for a more detailed explanation of the retrieval of the information within the BuB system from the field devices FG1. , .FGN in the user facilities N1. , .Nn.

According to FIG. 4 is on a user personal computer 30, an exemplary embodiment of the user facilities N1. , .NN represents, a browser device 31 installed. The user personal computer 30 is connected to a field device 33 via an IP network 32 , which can include the proxy server 2 , the star coupler 3 , the modem 4 , the modem 5 and the telecommunications network 6 . The field device 33 has an HTTP server 34 . In the field device 33 HTML pages 35 are stored comprising specific for this field device 33 information. The HTML pages 35 contain, for example, an HTML representation of the front view of the field device 33 . The HTML pages 35 are specially matched to the field device 33 and can be called up by the user personal computer 30 by means of an HTTP download from the HTTP server 34 of the field device 33 . The request for the HTML pages 35 from the field device 33 can be triggered by entering a URL (URL - “Uniform Resource Locator”) in the browser device 31 or by means of the reference from another HTML page (“link”) , In addition to the HTML pages 35 , the field device 33 provides a series of raw data 36 (measured values, parameters, etc.) in the form of files. The HTML pages 35 contain references to the raw data 36 available in the field device 33 . If the raw data 36 are to be evaluated or changed in some other way, a program is required which can generate high-quality data formats according to certain algorithms. These data formats can then be used by the program, for example for displaying the screen in connection with analysis options. The computing power required for this is generally not available in the field device 33 . With the help of the browser device 31 , the user has the option of using the IP network 32 via communication links (modem, telephone networks, LAN - "Local Area Network", WAN - "Wide Area Network") on the HTML pages 35 to access from the field device 33 and thus also the raw data 36 of the field device 33 referenced herein. FIG. 5 is (are) device browser 31 first, the HTML page (s) 35 required for this purpose with the help of the user of personal computer 30. After the HTTP server 34 of the field device 33 has provided the HTML page (s) 35 , including the references to the raw data 36 contained therein, the HTML page 35 and the raw data 36 are transmitted to the user personal computer 30 . Here, the HTML page 35 and the raw data 36 are transmitted by means of separate protocols between the field device 33 and the user personal computer 30 , preferably HTTP or RPC protocol. The raw data 36 can then be processed in the user personal computer 30 using suitable programs. To execute the RPC protocol, the field device 33 additionally comprises an RPC server 34 a.

When downloading the HTML page 35 from the HTTP server 34 , the referenced files of the raw data 36 can also be loaded automatically. The call from HTML page 35 can look like this: <EMBED SRC = "rawdata.ext">. The file with the raw data 36 of the field device 33 is referenced with the parameter “SRC”. In addition, the downloading of the raw data 36 can also be triggered via a link on the HTML page 35 to be activated by the user. In this case, the call in HTML page 35 could look as follows:
<a href = "rawdata.ext" type = "mime type"> link </a>.

So that the browser device 31 can start the correct program for the further processing of the raw data 36 , the browser device 31 must be informed of the content type of the raw data 36 . Depending on the operating system used by the user personal computer 30 and the browser device 31 used, there are different procedures for this. Both the file extension (for example "* .ext") and the MIME type (MIME - "Multipurpose Internet Mail Extension") supplied by the HTTP server 34 can be evaluated. The program for raw data processing started by the browser device 31 takes over the conversion of the downloaded raw data 36 . The program for raw data processing can be implemented as a browser plug-in, as an ActiveX component or as an external program.

A distinction must be made between different types of raw data. The processing of sporadically generated raw data 36 is preferably carried out with the aid of a browser plug-in or an Active X component. In this context, the data is accessed using the TCP protocol. If continuously updating raw data 36 are to be processed in the form of an endless data stream, then it makes sense to use a more effective protocol for the transmission to the user personal computer 30 (the user devices N1.. .NN). With the aid of the additional RPC protocol, the user devices N1. , .NN (or the user personal computer 30 ) information to be displayed about the field device (s) FG1. , .FGN or 33 in static and dynamic information. The static information is transmitted using the HTTP standard protocol, while the dynamic, ie changeable, data is transmitted via the more effective RPC protocol. The effort that would be incurred when establishing the dynamic data using the HTTP protocol by establishing / closing the connection and monitoring the connection would exceed the event-dependent, repeated transmission of the dynamic data using the RPC protocol. Since usually only a few data are to be transmitted quickly (measured values, message lists,...), The use of a connectionless protocol, in particular the RPC protocol, is advantageous for the dynamic data. When remote procedures are called (RPC), a local program calls a procedure on a remote system. The concept of the remote procedure call ensures that the entire network code remains hidden in the RPC interface and in the network routines. This avoids that the application programs (client and server) focus on details such as B. Conversion EBCDIC ↔ ASCII, number conversion, socket, session etc., must take care of. One goal of RPC is to simplify the implementation of distributed applications. UDP ("User Defined Protocol") is used by some applications that can only send short messages and can repeat them. UDP is therefore an ideal protocol for distributing information that is constantly changing, such as stock exchange prices. Instead of putting the data in a TCP envelope and then in the IP envelope, they now migrate to a UDP envelope before they come into the IP envelope. Although UDP is located on the same layer as connection-oriented TCP, it is a connectionless protocol. The use of the UDP protocol always makes sense if only a few data are to be transferred quickly. There is an exchange of short requests and answers in application programs between client and server. In this case, the effort involved in establishing / closing the connection and monitoring the connection would exceed that of sending the data again. The separate transmission of static and dynamic data between the field devices FG1. , .FGN in the device network and the user facilities N1. , .NN in the company intranet using different protocols is optimized by the provision and specific training of the proxy server 1 described in detail later.

The use of the RPC protocol for calling up the dynamic data in a client / server arrangement (user devices N1.. .NN / field devices FG1.. .FGN) is described below with reference to the schematic illustration in FIG. 6.

• a) Ein innerhalb des Brwosers 31 (vgl. Fig. 4) ablaufender Client-Prozess 100 ruft eine RPC-Schnittstelle 101 auf. Dieser Client-Prozess 100 kann z. B. ein in eine HTML- Seite eingebettetes Java-Applet sein. Die RPC- Schnittstelle 101 hat die Aufgabe, den Unterprogrammeinsprung zu spezifizieren. Die Spezifikation enthält den Namen der Funktion sowie Anzahl und Typen der Parameter. Hiermit wird ein logischer Einsprung definiert. Die RPC- Schnittstelle 101 ermöglicht das Starten der entfernt liegenden Prozedur 102.
• b) Die Parameter des Client-Prozesses 100 werden von der RPC-Schnittstelle 101 gelesen. Der Zweck der RPC- Schnittstelle 101 liegt in der Verpackung und Konvertierung der Parameter für das Serverprogramm.
• c) Die Netzroutinen versenden die Nachrichten an einen Server-Prozess 103, der im RPC-Server 34a abläuft.
• d) Eine RPC-Schnittstelle 104 des Server-Prozess 103 baut die Parameter aus den Nachrichtenpaketen wieder auf.
• e) Im nächsten Schritt wird das Serverprogramm aufgerufen. Dazu wird ein Serverstub definiert. Dieser Stub ist der eigentliche Einsprung in die auf dem Server-Prozess 103 liegende Prozedur.
• f) Nach Abarbeitung der Prozedur wird die Kontrolle wieder an die RPC-Schnittstelle 104 gegeben.
• g) Die Schnittstelle 104 verpackt die Rückgabeparameter und transportiert die Daten anschließend zu den Netzroutinen.
• h) Die Netzroutinen transportieren die Daten über netzwerkabhängige Aufrufe auf den Client-Prozess 100.
• i) Die RPC-Schnittstelle 101 des Client-Prozesses 100 entpackt die Parameter und versorgt die angegebenen Parameter mit den neuen Daten.
• j) Die Kontrolle wird an den Client-Prozess 100 zurückgegeben, der die erhaltenen Daten weiterverarbeiten kann.

An RPC call runs as follows, for example:

• a) A client process 100 running within browser 31 (cf. FIG. 4) calls an RPC interface 101 . This client process 100 can e.g. B. be a Java applet embedded in an HTML page. The RPC interface 101 has the task of specifying the subroutine entry. The specification contains the name of the function and the number and types of parameters. This defines a logical entry. The RPC interface 101 enables the remote procedure 102 to be started .
• b) The parameters of the client process 100 are read by the RPC interface 101 . The purpose of the RPC interface 101 is to package and convert the parameters for the server program.
• c) The network routines send the messages to a server process 103 , which runs in the RPC server 34 a.
• d) An RPC interface 104 of the server process 103 rebuilds the parameters from the message packets.
• e) In the next step, the server program is called. A server stub is defined for this. This stub is the actual entry into the procedure lying on the server process 103 .
• f) After the procedure has been processed, control is passed back to the RPC interface 104 .
• g) The interface 104 packs the return parameters and then transports the data to the network routines.
• h) The network routines transport the data to the client process 100 via network-dependent calls.
• i) The RPC interface 101 of the client process 100 unpacks the parameters and supplies the specified parameters with the new data.
• j) Control is returned to the client process 100 , which can process the received data further.

The concept of the remote procedure call ensures that the entire network code in the RPC interface and in the Network routines remains hidden. This avoids that the application programs (client and server) Details such as B. conversion EBCDIC ↔ ASCII, Number conversion, socket, session etc., must take care of. On Advantage of using the RPC protocol for the dynamic data is simplifying the implementation of distributed Applications.

Operating the field devices

The retrieval of information from the field device 33 , which includes the HTTP server 34 , described in connection with FIG. 4, can also be used in connection with actions within the scope of the observation and operating system, which are carried out for the purpose of operating the field device 33 , This makes it possible to operate the field device 33 with the aid of the browser device 31 . This is described in more detail below.

The field device 33 contains a storage device 35 a, in which operating software is stored in the form of HTML pages 35 , and a Java archive or data from which HTML pages can be generated. The operating software is specially tailored to the field device 33 . When the user enters the URL address of the field device 33 , an HTTP download starts, which leads to the downloading of the operating software from the HTTP server 34 of the field device 33 into the user personal computer 30 . After downloading the operating software from the field device 33 to the user personal computer 30 in the form of the HTML page (s) 35 , the front view of the field device 33 is shown with all operating and display elements within the browser device (cf. FIG. 3). The user can then trigger certain operating functions of the field device 33 with the aid of a mouse click on the screen of the user personal computer 30 . The user action is transmitted to the field device 33 by means of a fast and effective protocol which, on the one hand, transmits the above-mentioned operating requirements from the user personal computer 30 to the field device 33 and, on the other hand, reads back reactions from the field device 33 . For this purpose, the internal operating and display functions of the field device 33 to the interface of the browser device 31 are published, for. B. keyboard buffer, display buffer, LED status.

As part of the operation by the user, there is an exchange of short requests and responses between the user personal computer 30 and the field device 33 in the context of a client-server relationship. The effort involved in setting up / clearing down and monitoring the HTTP connection between the user personal computer 30 and the field device 33 would exceed the effort involved in retransmitting and receiving the data in accordance with a connectionless protocol. Since usually only a few data are to be transmitted quickly (e.g. key press, display content, LED status), the use of a fast, effective, connectionless protocol makes sense, for example the RPC protocol described above. Methods for compressing data are used to reduce the amount of data exchanged (eg display content) between the user personal computer 30 and the field device 33 .

Internet protocols, such as TCP / IP and HTTP, do not offer any security mechanisms. Additional protocols are required to enable secure communication. The mechanisms for protecting security-related actions on the field device 33 via TCP / IP communication are of particular importance. With regard to protection against unauthorized access, the operating actions on the field device 33 can be classified (cf. Table 1). Table 1

• - Mit Hilfe einer Firewall (z. B. Proxyserver) kann das interne Netz (Firmen-Intranet/LAN) eine geschützte Verbindung mit einem anderen Netz (z. B. Internet) aufnehmen.
• - Das Feldgerät 33 ist im Lieferzustand so eingestellt, dass Tasten, die die vollständige Eingabe von Kundenpasswörtern ermöglichen, gesperrt sind. Diese Sperre muss vom Kunden am Feldgerät 33 selbst bzw. mit dem Bedienprogramm in der Browser-Einrichtung 31 auf dem Nutzer-Personalcomputer 30 aufgehoben werden (Passworteingabe erforderlich). Im Lieferzustand sind damit nur einfache Bedienhandlungen über die Browser- Einrichtung 31 möglich: Navigation im Bedienmenü, Anzeige von Messwerten, Parametern und Meldungslisten.
• - Die Parametrierung des Feldgeräts 33 in der Frontansicht- Emulation ist mit Kenntnis der Passwörter wie am Feldgerät 33 möglich, wenn die Sperrung der dazu benötigten Tasten gelöst ist.
• - Sicherheitsrelevante Aktionen am Feldgerät 33 (Schalten, Steuern, Löschen von Puffern, . . .) werden durch Authentifikationsprotokolle geschützt, z. B. mittels Hash-Funktion und eines vom Feldgerät 33 generierten Schlüssels. Damit können aus dem Verbindungsprotokoll keine Rückschlüsse auf eingegebene Passwörter erfolgen. Mit diesem Verfahren wird aus einer beliebig langen Nachricht eine 128 Bit lange Information, der sogenannte "Message Digest", gebildet, der an die originäre Nachricht angehangen wird. Der Empfänger (Feldgerät 33) vergleicht den "Message Digest" mit dem vom Feldgerät 33 aus der Information ermittelten. Dadurch werden Feldgerätepasswörter nicht über die Kommunikationsverbindung übertragen.
• - Die im Feldgerät 33 generierten Schlüssel verfallen nach kurzer Zeit und können nur einmal für eine Übertragung verwendet werden. Damit ist die Aufzeichnung von sicherheitsrelevanten Protokollen und eine spätere Wiederholung dieser aufgezeichneten Protokolle wirkungslos.

Abusive actions when operating the field device 33 can essentially be excluded by the following measures:

• - With the help of a firewall (e.g. proxy server), the internal network (company intranet / LAN) can establish a protected connection with another network (e.g. Internet).
• The field device 33 is set in the delivery state in such a way that keys which allow the complete entry of customer passwords are blocked. This lock must be lifted by the customer on the field device 33 itself or with the operating program in the browser device 31 on the user personal computer 30 (password entry required). In the delivery state, only simple operating actions are possible via the browser device 31 : navigation in the operating menu, display of measured values, parameters and message lists.
• - The parameterization of the field device 33 in the front view emulation is possible with knowledge of the passwords as on the field device 33 if the lock of the keys required for this is released.
• - Security-relevant actions on the field device 33 (switching, controlling, deleting buffers,...) Are protected by authentication protocols, e.g. B. by means of a hash function and a key generated by the field device 33 . This means that no conclusions can be drawn about entered passwords from the connection log. With this method, 128-bit information, the so-called "message digest", is formed from an arbitrarily long message and is appended to the original message. The receiver (field device 33 ) compares the "message digest" with that determined by the field device 33 from the information. As a result, field device passwords are not transmitted via the communication link.
• - The keys generated in the field device 33 expire after a short time and can only be used once for a transmission. This means that the recording of security-relevant logs and a later repetition of these recorded logs is ineffective.

proxy server

An element for the optimized implementation of the described functional interaction of the elements of the observation and operating system, for example the use of the RPC protocol, the retrieval of the raw data from the field devices FG1. , .FGN and the operation of the field devices using a browser on the user devices N1. , .NN, is the proxy server 1 . Known standard HTTP proxy servers only support the HTTP protocol and are therefore not able to serve as a gateway between the device network and the company intranet. For this reason, a specific proxy server 1 designed for the BuB system was created, both of which are provided by the field devices FG1. , .FGN protocols used (HTTP, RPC) are supported.

A major advantage that when using the proxy server 1 compared to the coupling of the device network to the company intranet using a router or, if there is no WAN connection (WAN - "Wide Area Network") between the device network and the intranet, a direct coupling of the device network segment via a hub or a switch consists in the use of so-called "caching".

The principle underlying this process ("caching") is general below, without reference to the above mentioned figures, briefly described.

A client makes a request for an object to a Server setup, this request initially runs through a so-called proxy facility. The proxy device looks according to whether the object in question is already in a local Memory (cache) of the proxy device, which is in is usually formed on a hard disk. Here found that the object is not locally in memory the proxy device passes the request on an actual target server setup. From there, the Proxy set up the object and save a copy of the Object for further requests for this object in the local Store before the proxy device sends the object to the passes on the requesting client. However, if the object is in local memory of the proxy device is found, so the Client request not to the target server facility put through, but the client gets the desired object transmitted directly from the proxy device. requirement for optimal execution of the described method is a sufficiently large memory area in the proxy device, d. H. in the order of several hundred MB to several GB. Otherwise the local memory runs in the proxy Setup over and there must be a "garbage collector" (a so-called clean-up service) started, the outdated Filters objects out of memory to make room for new ones To create objects.

Advantages of the described method ("caching") are: one Performance improvement (faster Data transport as external); a saving of external bandwidth (more space for other services remains free); a Reduction of response times Relief of the target server setup; when transporting the Objects from the proxy device to the client are not created or lower transmission costs; and the hit rates in The proxy facility's local storage may vary depending on usage be very high.

The proxy server 1 used to connect the device network and the company intranet (see FIG. 1) is based on the described basic principle and, due to the specific design, which will be described in detail later, also has the advantages mentioned below.

The use of the proxy server 1 (cf. FIG. 1) results in significant speed advantages when accessing the device network. The proxy server 1 comprises a file memory or file cache optimized for use in the BuB system, all of which come from the field devices FG1. , .FGN retrieves files with static data in proxy server 1 . If such a file is accessed for the first time, then this file must be directly from one of the field devices FG1. , .FGN can be fetched. If this file is accessed again, however, it can then be delivered directly from the file cache of the proxy server 1 . Since the local company intranet is generally much faster than a modem connection to the field devices FG1. , .FGN, there are significant speed advantages when accessing the device network, since only the dynamic data, which is significantly smaller compared to the HTML pages and the Java archives, is transmitted via the slow modem connection.

The proxy server 1 also increases security in the network. The proxy server 1 seals off the two networks, device network and company intranet, from one another and only transmits the protocols processed in the proxy server 1 . This means that from the company intranet only those from a browser on the user facilities N1. , .NN to the field devices FG1. , .FGN generated requirements are transferred. In the opposite direction, only those from the field devices FG1. , .FGN generated responses transmitted. This means that all other data packets circulating on the company intranet are kept away from the device network and therefore do not influence the throughput in the device network. Furthermore, a high data volume occurring in the device network can occur due to cross communication between the field devices FG1. , .FGN do not increase the network load on the company intranet.

The use of the RPC protocol by means of the proxy server 1 has the advantage that it is ensured that the field devices FG1 can be accessed. , .FGN remains restricted to the company intranet connected to proxy server 1 . A company intranet is usually connected to the Internet via an HTTP gateway. This gateway takes on a firewall function here (see FIG. 7) by blocking the transmission of the RPC protocol. As a result, the data of the field devices FG1 can no longer be accessed outside the company intranet. , .FGN can be accessed because all dynamic data of the field devices FG1. , .FGN can be transmitted via the RPC protocol.

• - Es wird eine eigene Homepage zur Verfügung gestellt, über die alle angeschlossenen Feldgeräte FG1. . .FGN erreichbar sind.
• - Die angeschlossenen Feldgeräte FG1. . .FGN werden automatisch adressiert und erkannt; Darstellung dieser Feldgeräte FG1. . .FGN in der Homepage als Startseite auf den Nutzereinrichtungen N1. . .NN für einen direkten Gerätezugriff.
• - Es wird der Zugriff über Gerätenamen der Feldgeräte FG1. . .FGN ermöglicht, dies ist gegenüber dem Zugriff über die IP-Adresse nutzerfreundlicher.
• - Der Proxyserver 1 kann mittels Browser auf den Nutzereinrichtungen N1. . .NN konfiguriert werden (e-mail-Adressen, Telefon-Nummern, Gerätenamen, . . .)
• - Der Proxyserver 1 definiert die möglichen Zugriffswege ("Firewall-Funktion").
• - Der Proxyserver 1 kann Daten aus den Feldgeräte FG1. . .FGN zwischenspeichern. Diese Funktion eignet sich z. B. für die Protokollierung der Störfallinformationen oder der Betriebsmesswerte. Diese Daten werden intern in einer XML- Datenbank (XML - "Extended Markup Language") abgelegt.
• - Der Proxyserver kann die aus den Feldgeräten FG1. . .FGN über das RPC-Protokoll übertragenen Daten im XML-Format zur Verfügung stellen. Hierdurch können beispielsweise nutzerspezifische Erweiterungen der im Proxyserver 1 verfügbaren Darstellungen vorgenommen werden. Hierzu steht ein im Proxyserver 1 integrierter XSL-Parser (XSL - "Extended Stylesheet Language") zur Verfügung.
• - Durch die mit Hilfe des XSL-Parsers realisierbaren Filter auf die XML-Datenbank kann der Proxyserver 1 ebenfalls als Client für weitere Applikationen genutzt werden.
• - Signalisierung von Ereignissen im LAN (LAN - "Local Area Network") via e-mail ist möglich. Der Proxyserver 1 stellt eigene e-mail-Postfächer zu Verfügung, die mittels eines POP3-Clients (POP3 - "Post Office Protocol Stepping 3"), wie z. B. Outlook, abgerufen werden können. Weiterhin ist eine Weiterleitung von e-mails an ein anderes Postfach mittels eines im Proxyserver 1 integrierten SMTP-Servers (STMP - "Simple Message Transfer Protocol") möglich.

The proxy server 1 enables a wide range of functions, which with the previously customary direct access to the field devices FG1. , .FGN are not available. The following compilation lists further essential functions that result in connection with the following detailed description of the proxy server 1 :

• - A separate homepage is made available via which all connected field devices FG1. , .FGN are available.
• - The connected field devices FG1. , .FGN are automatically addressed and recognized; Representation of these field devices FG1. , .FGN in the homepage as homepage on the user facilities N1. , .NN for direct device access.
• - There is access via device names of the field devices FG1. , .FGN enables, this is more user-friendly than access via the IP address.
• - The proxy server 1 can use a browser on the user devices N1. , .NN can be configured (e-mail addresses, telephone numbers, device names,...)
• - The proxy server 1 defines the possible access routes ("firewall function").
• - The proxy server 1 can receive data from the field devices FG1. , Cache .FGN. This function is suitable for. B. for logging the accident information or the operational measured values. This data is stored internally in an XML database (XML - "Extended Markup Language").
• - The proxy server can from the field devices FG1. , Provide .FGN data transmitted in XML format via the RPC protocol. In this way, for example, user-specific extensions of the representations available in the proxy server 1 can be carried out. For this purpose, an XSL parser (XSL - "Extended Stylesheet Language") integrated in the proxy server 1 is available.
• - Thanks to the filters on the XML database that can be implemented using the XSL parser, the proxy server 1 can also be used as a client for other applications.
• - Signaling of events in the LAN (LAN - "Local Area Network") via e-mail is possible. The proxy server 1 provides its own e-mail mailboxes that can be used by means of a POP3 client (POP3 - "Post Office Protocol Stepping 3 "), such as. B. Outlook, can be accessed. It is also possible to forward e-mails to another mailbox using an SMTP server (STMP - "Simple Message Transfer Protocol") integrated in the proxy server 1 .

The design of the proxy server 1 is described in more detail below.

FIG. 7 shows an arrangement with the device network and the company intranet according to FIG. 1, elements of the proxy server 1 being shown schematically. Fig. 8 shows functional blocks of the proxy server 1 in a block diagram.

According to Fig. 7, each of the field devices FG1. , .FGN a respective HTTP server HS1. , .HSN, which correspond to the respective HTTP server 34 (cf. FIG. 4) and are connected to a star coupler 39 . The proxy server 1 also has an HTTP server 40 . The operation of the proxy server 1 will now be described with reference to FIG. 8.

The proxy server 1 is always accessed from the local network of the company intranet in which the user devices N1 are located. , .NN with the respective modem connection are located in the device network comprising the field devices, which can comprise a substation or several substations. If one of the user devices N1. , .NN addressed via the associated local IP address as a server, this access is forwarded to the HTTP server 40 via a TCP / IP stack 41 (TCP - "Transfer Control Protocol").

The HTTP server 40 delivers the requested files to the company intranet. For this purpose, the HTTP server 40 uses a file filter 42 to contact a cache manager 43 . The file filter 42 typically forwards the request to the cache manager 43 . Only certain requests are recognized based on the requested file type and sent to another processing path. These exceptions are described later. The cache manager 43 first tries to find the requested file in the local files 44 or in a file cache 45 . If the requested file is neither a local file of the proxy server 1 nor in the file cache 45 , the file request is forwarded to an HTTP client 46 . This establishes a connection to the HTTP server HS1,... Via a further TCP / IP stack 47 . , , or HSN of the addressed field device FG1,. , , or FGN in the device network in order to obtain the requested file from there.

A modem connection with the PPP protocol is preferably used as the connection to the device network (cf. FIG. 1). However, since the proxy server 1 has several connections to different field devices FG1 via this modem connection. , .FGN, an arbitation of this modem connection is required, since the PPP protocol can only manage a point-to-point connection. A block slot protocol 48 is used for this . This protocol allocates time slices on the modem communication link to the individual PPP connections and thus prevents collisions between the individual connections. The block slot protocol 48 is also responsible for all field devices FG1 active in the device network. , .FGN recognizable. For this purpose, the device network is searched cyclically for active field devices. The detected active field devices are entered by a device manager 49 into an XML database 50 of the proxy server 1 .

The XML database 50 is a data tree stored according to the standardized "Document Object Model". Now contains a user device N1,... Connected to the proxy server 1 via the HTTP server 40 in the browser. , , or NN loaded HTML page Java code that establishes a parallel UDP connection (UDP - "User Defined Protocol") for the RPC protocol, then an RPC server 51 is addressed from the company intranet in this way , Since the RPC protocol is based on the standardized UDP / IP protocol for performance reasons, a connection management 52 must be contained here in the proxy server 1 , since the UDP protocol does not operate in a connection-oriented manner. The connection manager 52 ensures that for each usage device N1. , .NN a separate communication port for an RPC client 53 of the proxy server 1 is reserved in the device network from the company intranet. The RPC requests from the company intranet are then forwarded directly to the device network via the RPC client 53 of the proxy server 1 .

The answers of the field devices FG1. , .FGN on RPC requests are forwarded to the RPC server 51 . This gives the answer of the respective field device FG1,. , , or FGN to the user facilities via the company intranet. At the same time, the dynamic data currently transmitted in the RPC protocol from the respective field device FG1,. , , or FGN are stored in the XML database 50 in the proxy server 1 .

The data stored in the XML database 50 can be converted into any other data formats using an XSL parser 54 integrated in the proxy server 1 . The transformation instructions required for this must be stored locally in proxy server 1 as an XSL script file. In order to trigger such a transformation process, an * .XML file must be requested from the HTTP server 40 . Such a request is filtered out of the normal access path to the cache manager 43 by the file filter 42 connected to the HTTP server 40 and forwarded to the XSL parser 54 . This reads an XSL file of the same name from the files stored locally in proxy server 1 in addition to the requested XML file and starts the transformation process. The result of this transformation is sent from the HTTP server 40 to the requesting user. In this way, e.g. B. HTML files dynamically from an XSL template with the current data of the field devices FG1. , .FGN generated from the XML database 50 or simply a subtree of the database can be transferred as an XML file.

The file filter 42 , the cache management 43 , the local files 44 , the file cache 45 , the XSL parser 54 and the XML database 50 form a file system of the proxy server 1 .

Individual function blocks of the proxy server 1 are described in more detail below.

HTTP server

First of all, the basic mode of operation of the HTTP server 40 embodied in the proxy server 1 (see FIG. 8) is explained, some essential basics of the HTTP being described for better understanding.

As with other application protocols on the Internet, HTTP (HTTP - "Hypertext Transfer Protocol") is an ASCII protocol that uses a secure TCP connection between a client (computer of the Internet user) and a server (server device) for data exchange which accessible internet content - data - is available). Port 80 is defined as the connection point, ie an HTTP server listens to new client connections at this port. Alternatively, the vast majority of HTTP server software can also be instructed via a corresponding configuration dialog to use a different port for establishing contact.

Unlike other protocols, e.g. B. FTP (FTP - "File Transfer Protocol") and POP3, a connection between an HTTP client and an HTTP server is very short-lived. The HTTP client establishes a TCP connection to the desired HTTP server via port 80 and sends a request for a desired document to the HTTP server. The HTTP server receives the request, evaluates it and, if successful, sends the desired document back to the HTTP client. The HTTP server closes the TCP connection automatically after it has sent the HTTP client the requested document or an error message in response to its request.

An important functionality of HTTP is that the HTTP Client can tell the HTTP server what type of data this can understand. So there must be one for each request Communication between the HTTP client and the HTTP server about how the data should be transferred. This communication creates a so-called surplus or Overhead; HTTP is therefore also considered stateless Protocol ("stateless protocol") called because the Connection does not go through several phases, from logging in via Data exchange through to logging out through the HTTP client. On the one hand, this facilitates the development of HTTP Client / HTTP server software, but is in terms of Not much use of the available bandwidth efficient.

The HTTP protocol is used to access sources in the Obtain URL format (URL - "Uniform Resource Locator"). The HTTP client, usually a web browser on the computer of the internet user. It requires an HTML page and then generates a sequence of requests regarding the File references in this HTML page. Then the user probably a link in the requested HTML page click, and the HTTP client sends a request for of the HTML pages linked to this link, to the same or another HTTP server. These others Communication links no longer have information about one previous connection. This works with simple ones Client / server environments. For larger ones This way of working can be a problem for communications, because for every little amount of data that is transmitted this excess ("overhead") is incurred, which the Efficiency reduces.

Fig. 9 shows a schematic representation of the syntax of a request in connection with an HTTP client / server interaction.

The HTTP client / server interaction consists of a single request / response communication. It comprises a "request line", one or more optional "request header fields" and an optional "entity body". A TCP connection to the HTTP server 61 is opened 62 from the HTTP client side 60 , that is to say generally from the Internet browser. The HTTP client 60 then sends a command string to the HTTP server 61 . The HTTP server 61 responds via the TCP connection opened by the HTTP client 60 with a header which, in addition to the HTTP version supported by the HTTP server 61 , also contains the MIME type and the coding of the requested file. The HTTP server 61 appends the content of the requested file to this header in ASCII format. After the HTTP server 61 has sent the complete file, it closes the TCP connection 63 opened by the HTTP client 60 again. This process can be repeated any number of times.

• 1. "connection" (Verbindungsaufbau)
  • - WWW-Client baut eine TCP/IP-Verbindung zum WWW-Server auf
• 2. "request" (Anforderung)
  • - Angabe einer Zugriffsmethode (GET, HEADER, POST . . .)
  • - Spezifikation des gewünschten Dokumentes mittels URL
  • - Zusatzinformationen in Form von MIME-Header
  • - Daten (bei POST)
• 3. "response" (Antwort)
  • - Header mit Statuscode
  • - Zusatzinformationen in Form von MIME-Header
  • - Dokument in HTML-Format
  • - Daten in sonstigen Formaten (Bilder, Sound . . .)
• 4. "close" (Verbindungsabbau)
  • - Im Normalfall vom HTTP-Server aus, nach Datenübertragung
  • - Im Spezialfall vom HTTP-Client aus (Übertragungszeit, Speicherplatz)

The following compilation shows the process of a typical HTTP access:

• 1. "connection"
  • - WWW client establishes a TCP / IP connection to the WWW server
• 2. "request"
  • - Specify an access method (GET, HEADER, POST...)
  • - Specification of the desired document using URL
  • - Additional information in the form of MIME headers
  • - data (at POST)
• 3. "response"
  • - Header with status code
  • - Additional information in the form of MIME headers
  • - Document in HTML format
  • - Data in other formats (pictures, sound...)
• 4. "close" (disconnection)
  • - Usually from the HTTP server after data transfer
  • - In special cases from the HTTP client (transmission time, storage space)

The "request line" consists of three text fields separated by spaces. The first field specifies the method (or the command). The second field specifies the name of the source (is the URL without specifying the protocol and the host). The last field specifies the protocol version of the HTTP client 60 used , for example HTTP / 1.0. The "request header fields" transfer additional information about the request and the HTTP client 60 . The fields are used as a kind of RPC parameter. Each field consists of a name, followed by a colon and the field value. The order of the "header fields" is not important here. The entity body is sometimes used by HTTP clients 60 to send larger packets of information to the HTTP server 61 .

file cache

In order to enable the cache manager 43 to work as efficiently as possible, the file cache 45 does not work as usual with the URL, the date and the lifespan of the files to be managed, but uses other criteria for identifying a file. If only the three criteria mentioned were used to decide whether a file locally in the file cache is identical to the file available in the field device, then a comparison of the file characteristics mentioned would be necessary to carry out this test. To do this, the header from the field device would have to be requested for each file. Since the file system of the field devices FG1. , However, .FGN can only be loaded as a unit in the form of a KON file (converted files - format that can be loaded into user devices N1. .NN files), such a comparison is not necessary for every file. The dynamics in the field devices FG1 are an exception here. , .FGN generated files, for example the file MLFB.TXT (MLFB - machine-readable manufacturer name), which are not from the file system of the field devices FG1. , .FGN, but from the field device FG1,. , , or FGN set MLFB is generated.

An entry in a file "nocache.txt" serves as a distinguishing feature between these two file forms, namely the static files and the files with dynamic data. All dynamically in the field devices FG1. , Files generated by .FGN must be listed in this file. Static files are generated by the HTTP server HS1. , .HSN of field devices FG1. , .FGN marked with an infinite lifespan. The following is an example of the content of the nocache.txt file:
/mlfb.txt: MLFB, BF No., display type
/textpool.zip: device-specific texts for applets
(multilingual)
/ver.txt: version, date
/chartab.jar: device character set

The file "ver.txt" can have the following content:
V01.01.01
Do, Oct 24, 2000 7:50:00 AM GMT

Slot protocol of the proxy server

The slot protocol 48 (cf. FIG. 8) serves to connect the proxy server 1 to the field devices FG1. , .FGN in an arrangement with a star coupler according to FIG. 7. The slot protocol 48 is divided into the two areas (i) device detection and (ii) arbiting of the star coupler arrangement. The device detection is used for the automatic detection of all field devices FG1 connected to the star coupler 39 . , .FGN. The arbitration must involve collisions between datagrams of different field devices FG1. , .FGN on the communication link between the proxy server 1 and the individual field devices FG1. , Prevent .FGN.

The device detection when using the star coupler arrangement 39 is described below.

device Discovery

The device identification constitutes a component of the slot protocol 48. This part of the protocol occupies the serial connection exclusively, ie no other communication may be active on the modem link during the device identification. For this reason, device recognition is only activated when the modem connection is established. This part of the protocol is inactive while the monitoring and operating system is running. However, device detection can be activated if necessary.

Fig. 10 is a master-slave arrangement is shown with a star coupler for explanation of the device discovery.

The slot protocol 48 works according to the master-slave principle. A master 70 is located at the upper connection in FIG. 10. The lower connections of a star coupler 71 , which corresponds to the star coupler 3 in FIG. 1, are each provided by a slave S1. , .SN shows which field devices FG1. , .FGN according to FIG. 1 correspond. The master 70 could address every possible address of the connected slaves S1. , Query .SN and, in response to this query, find slave S1,. , , or SN in the list of devices known to master 70 . However, this procedure can no longer be carried out with an address range of 32 bits. Here 2 ^ 32 queries would be required. However, this number can no longer be carried out, since the time required for this query would exceed the lifespan of the system. In order nevertheless to be able to automatically recognize the devices connected to the master 70 , the problem is solved according to the invention in the following way:

In the case of an addressing scheme with a binary-coded address with a predefined address length, an address range is always queried when an inquiry is made. Only the slaves that are in the queried address range respond to this request. Since there can be several field devices (slaves) in the same queried address range, there is a simultaneous response from several of the slaves S1. , .SN inevitably leads to a collision in this case. This collision is deliberately accepted and is part of the proposed procedure. For this reason, the master 70 only checks whether an answer to its request has been received within a defined period of time.

Is the address space of the addressable slaves S1. , .SN n bits, the master 70 sends out a request with a fixed bit of the address and a mask for the other address bits. Two queries can be used to test whether there are slaves in the address range specified by the fixed bit. If a response to a request for an address area has been received, the mask is reduced by one bit and the next fixed bit is tested with two inquiries as to whether there are slaves in the now smaller address area. If there is an answer to the request for the now smaller address area, the next bit of the address area in which slaves are located is found. This process is repeated until the mask for the address area has been reduced to 0 bits. Then one of the slaves is S1. , .SN clearly identified on the bus. If answers to both states of the bit just tested come up during a query, then both branches are followed up in the next iteration. Since with a mask size of 0 bits only the device or the slave with the requested, now completely fixed address can respond to the request, no collisions can occur with the last request, and the response telegram from the slaves to be detected can provide spontaneous information included about the status of the connected slaves. FIG. 12 once again explains the described method using a simple addressing scheme with a 4-bit address, that is to say for an address space from 0 to 15 . It is assumed that the devices with addresses 3 , 4 and 7 are in the arrangement. The polling of the most significant bit is started. Address space 0 to 7 and, in a second query, address space 8 to 15 are therefore tested with one query. No device answers this second query. The master receives one or more answers to the first query. Therefore, the mask is reduced by an additional bit in address space 0 to 7 . Address ranges 0 to 3 are now checked with a third query and 4 to 7 with a fourth query. This process is repeated as shown in FIG. 12 until the addresses are completely resolved and all devices are found.

In the example described, the slaves S1. , .Sn or the field devices FG1. , .FGN connected to the Master 70 using an IP-based protocol. With the IP protocol, all bus users have a 32-bit address. The address is divided into octets and each octet is shown in decimal. The hexadecimal 32 bit number Ox8D8D8000 therefore corresponds to the IP address 141.141.128.0. A recursive variant of the procedure described in the previous paragraph is used for the actual process for device detection / interrogation.

Fig. 11 shows the flowchart of the method as Nassi- Sneidermann diagram.

In the context of the described method, the test as to whether a field device (slave) can be addressed in the available address range is preferably initiated by the master 70 with the aid of a request datagram known as such. In contrast to conventional methods, however, it is consciously accepted that several of the slaves S1 on a request datagram sent out by the master 70 . , Reply .SN at the same time. The fact that in the star coupler 71 all of the slaves S1. , .SN received signals are linked via a logical OR gate and this sum signal is forwarded to the master 70 , it can be ensured that in the master 70 a response from one of the slaves S1. , .SN is recognized in any case. If the response datagrams of several of the slaves S1. , .SN overlap in time, an incorrect datagram is received in master 70 . This case is also recognized as the answer.

By specifying a maximum response time for slaves S1. , .SN on a request datagram of the master 70 and the datagram transmission time, a monitoring time for the master 70 can be defined. If the master 70 receives a response within this monitoring time, there are slaves or field devices in the requested address range. Conversely, there are no field devices in the requested address area if no response to the request was received by the master 70 within the monitoring time.

Since with a complete resolution of the address in the request of the maters 70 (ie the mask becomes empty) only one of the slaves S1. , .SN is allowed to respond, no collision can occur in this case. In this case, the error protection of the received datagram can be used to rule out a line fault and thus a possible fault detection of a connected slave. If a line fault occurs during the monitoring time after a request from the master, which simulates a slave that does not exist, this only leads to an extension of the polling process, but not to incorrect detection of connected slaves, since this line fault occurs at the latest when the slave is completely resolved Mask is recognized.

The following paragraph shows the function of the method using an example:
Test: 141.141.128.0; Mask: 255.255.128.0;
Test: 141.141.0.0; Mask: 255.255.128.0;
Test: 141.141.64.0; Mask: 255.255.192.0;
Test: 141.141.96.0; Mask: 255.255.224.0;
Test: 141.141.64.0; Mask: 255.255.224.0;
Test: 141.141.80.0; Mask: 255.255.240.0;
Test: 141.141.88.0; Mask: 255.255.248.0;
Test: 141.141.80.0; Mask: 255.255.248.0;
Test: 141.141.84.0; Mask: 255.255.252.0;
Test: 141.141.86.0; Mask: 255.255.254.0;
Test: 141.141.84.0; Mask: 255.255.254.0;
Test: 141.141.85.0; Mask: 255.255.255.0;
Test: 141.141.84.0; Mask: 255.255.255.0;
Test: 141.141.84.128; Mask: 255.255.255.128;
Test: 141.141.84.0; Mask: 255.255.255.128;
Test: 141.141.84.64; Mask: 255.255.255.192;
Test: 141.141.84.0; Mask: 255.255.255.192;
Test: 141.141.84.32; Mask: 255.255.255.224;
Test: 141.141.84.0; Mask: 255.255.255.224;
Test: 141.141.84.16; Mask: 255.255.255.240;
Test: 141.141.84.0; Mask: 255.255.255.240;
Test: 141.141.84.8; Mask: 255.255.255.248;
Test: 141.141.84.0; Mask: 255.255.255.248;
Test: 141.141.84.4; Mask: 255.255.255.252;
Test: 141.141.84.0; Mask: 255.255.255.252;
Test: 141.141.84.2; Mask: 255.255.255.254;
Test: 141.141.84.3; Mask: 255.255.255.255;
Test: 141.141.84.2; Mask: 255.255.255.255;
Found: 141.141.84.2;
Test: 141.141.84.0; Mask: 255.255.255.254;
Test: 141.141.80.0; Mask: 255.255.252.0;
Test: 141.141.82.0; Mask: 255.255.254.0;
Test: 141.141.80.0; Mask: 255.255.254.0;
Test: 141.141.81.0; Mask: 255.255.255.0;
Test: 141.141.80.0; Mask: 255.255.255.0;
Test: 141.141.80.128; Mask: 255.255.255.128;
Test: 141.141.80.192; Mask: 255.255.255.192;
Test: 141.141.80.128; Mask: 255.255.255.192;
Test: 141.141.80.160; Mask: 255.255.255.224;
Test: 141.141.80.176; Mask: 255.255.255.240;
Test: 141.141.80.160; Mask: 255.255.255.240;
Test: 141.141.80.168; Mask: 255.255.255.248;
Test: 141.141.80.160; Mask: 255.255.255.248;
Test: 141.141.80.164; Mask: 255.255.255.252;
Test: 141.141.80.166; Mask: 255.255.255.254;
Test: 141.141.80.164; Mask: 255.255.255.254;
Test: 141.141.80.165; Mask: 255.255.255.255;
Test: 141.141.80.164; Mask: 255.255.255.255;
Found: 141.141.80.164;
Test: 141.141.80.160; Mask: 255.255.255.252;
Test: 141.141.80.162; Mask: 255.255.255.254;
Test: 141.141.80.163; Mask: 255.255.255.255;
Found: 141.141.80.163;
Test: 141.141.80.162; Mask: 255.255.255.255;
Test: 141.141.80.160; Mask: 255.255.255.254;
Test: 141.141.80.161; Mask: 255.255.255.255;
Found: 141.141.80.161;
Test: 141.141.80.160; Mask: 255.255.255.255;
Found: 141.141.80.160;
Test: 141.141.80.128; Mask: 255.255.255.224;
Test: 141.141.80.0; Mask: 255.255.255.128;
Test: 141.141.64.0; Mask: 255.255.240.0;
Test: 141.141.0.0; Mask: 255.255.192.0;
58 queries. , ,

The queries included the address space 141.141.0.0 to 141.141.255.255. The devices with the following addresses were found:
141.141.84.2
141.141.80.164
141.141.80.163
141.141.80.161
141.141.80.160

FIG. 12 illustrates the illustrated process in the form of a tree representation, the gray fields identifying the queries that are made by one or more slaves S1. , .SN or field devices were answered.

Broadcast service

For connecting the proxy server 1 to the field devices FG1. , .FGN can use an IP-based network instead of the simple architecture with star coupler 39 . In this case, it is not necessary to arbiter this network using a protocol, for example the slot protocol 48 . This function is performed by the network itself. In this embodiment, functions of the network can also be used for device detection. With a network connection between the proxy server 1 and the field devices FG1. , .FGN uses a broadcast service to configure the observation and operating system itself.

In both cases, detection of the connected field devices FG 1. , .FGN, d. H. in the embodiment with Star coupler arrangement and when using a network, especially one LANs, the detection when commissioning the Observation and operating system automatically executed and carried out without prior parameterization of those involved in the system Components.

The broadcast service is used to identify the field devices connected to the IP-based network (e.g. LAN) that contain a server for their own operation. The broadcast service also serves to collect spontaneous events that have occurred in the connected field devices. The broadcast service is an IP application and is therefore based on the functions of the IP stack and is based on the UDP protocol. For this service, server side z. B. a fixed port OxD000 reserved. A free port is dynamically selected on the client side. By using the standard UDP / IP protocol, you can use the IP programming interfaces of common operating systems, such as B. MS Windows or Linux. This allows the proxy server 1 to be easily ported to classic office servers.

The broadcast service is active both in proxy server 1 and in the individual field devices. For the broadcast service, proxy server 1 is defined as the master. A configuration query is a UDP telegram sent by the master. Depending on the configuration, this telegram is directed to a broadcast or a multicast IP address. A description of broadcast or multicast IP addresses can be found, for example, in Karanjit S. Siyan: Inside TCP / IP Third Edition, New Riders Publishing, Indianapolis, 1997, ISBN 1-56205- 714-6, page 187ff.

All field devices are then on the Answer the configuration query of the master with a UDP telegram, which contains the most important configuration data of the field device. Now that everyone is connected to the IP-based network In theory, field devices want answers at the same time there were initially some collisions on the bus used come through the CSMA / CD process (CSAM - "carrier sense, multiple access / collision detect "). One Description of this process is also in Karanjit S. Siyan: Inside TCP / IP Third Edition, New Riders Publishing, Indianapolis, 1997, ISBN 1-56205-714-6, page 97ff Find. The UDP response telegrams of all active field devices are thus within a certain range at the requesting master Time to arrive. The interrogator is thus able determine how many and which field devices are in the network are located, and can then be used by the field devices Information about the HTTP protocol or other IP-based Request logs.

The broadcast service also has the job of a Event occurring spontaneously in one of the field devices in the IP based network to the participants of the broadcast service to distribute. Because the field devices have no information have which master is responsible for this signal and on the other hand it may be possible that the IP based network multiple masters with distributed tasks exist, the event telegram is broadcast to everyone Network participants sent. The masters can use this signal depending on the event type and sender ignore or take an action trigger which via another protocol, e.g. B. HTTP, retrieves additional information from the field device. This Retrieve additional information on the event sending Field device by the responsible master also serves as Acknowledgment of receipt from the master. Will an event telegram not confirmed, then it will be regular Intervals (for example about 10 s or with a logarithmic growing time) repeated until a confirmation of one Master takes place.

Fig. 13 shows a schematic diagram for explaining the procedure in the context of the configuration query.

As a master, proxy server 1 sends a configuration request 72 as a broadcast to all participants in the network. All field devices FG1. , .FGN respond with a UDP datagram to the IP address of the master that sent the configuration request. As already shown, this UDP datagram contains the most important information about the connected devices.

device management

The management of the field devices or slaves recognized with the aid of the device recognition when using the star coupler 39 or the broadcast service is carried out in the proxy server 1 with the aid of the device management 49 (cf. FIG. 8). Fig. 14 is a schematic block diagram showing the connection of the device manager 49 in the proxy server 1.

The device manager 49 provides the cache manager 43 and the XML database 50 with information about the field devices FG1 recognized in the device network. , .FGN available. For this purpose, the device management 49 obtains its information about the connected field devices FG1. , .FGN from the procedure running in the context of the slot protocol 48 . In this way, the IP addresses of the connected field devices FG1. , .FGN provided. The device management 49 is from the slot protocol 48 with the information about the detected field devices FG1. , .FGN supplied. The slot protocol 48 only provides the device manager 49 with the IP addresses of the recognized field devices FG1. , .FGN. All further information about the field devices FG1. , .FGN, which are to be provided by the device management 49 in the proxy server 1 , are downloaded from the field devices FG1 by downloading HTTP data in defined files. , .FGN procured. Device management 49 uses the known IP addresses of all recognized field devices FG1. , .FGN the cache management 43 the following information about the field devices FG1. , .FGN available: field device type, field device version and version of the file block for the observation and operating system.

This information is also available in the file cache 45 (cf. FIG. 8) for the files already stored there. This means that when a file is requested from a specific one of the field devices FG1. , .FGN can be decided on the basis of this information as to whether the file present in file cache 45 is identical to the file available in the field device without reading the file header of the requested file from the specific field device. It is only necessary to compare the version information for the file in the file cache 45 with the information from the device management 49 for the IP address of the specific field device.

The connection of the device management 49 to the XML database 50 serves to provide information from the field devices FG1. , .FGN. This information is in the form of an XML file from the field devices FG1. , .FGN loaded. The following table shows an overview of the contents of this file:

All of this information is stored in a "DevData.xml" file. The device manager 49 initiates an HTTP download of this file if one of the field devices FG1. , .FGN from slot protocol 48 was found. All other files are only loaded from the field device by the device management 49 if their file path is contained in this XML file, ie all files encapsulated with a <DEV_PATH> tag are loaded.

The file "DevData.xml" is transformed into the internal format of the proxy server 1 in the proxy server 1 after downloading using the XSL parser 54 and then entered in the XML database 50 of the proxy server 1 .

XSL parser

The XSL parser 54 (cf. FIG. 8) is used to generate dynamically generated HTML files from the central XML database 50 of the proxy server 1 . For this purpose, XSL scripts stored locally in the proxy server 1 are used. The XSL scripts can be imported into proxy server 1 using an admin page.

Fig. 15 shows the integration of the XSL parser 54 in the proxy server 1.

Is an XML file from the user devices N1 via the HTTP server 40 . , .NN requested from the intranet, then this request is filtered out by the file filter 42 and forwarded to the XML front-end HTTP 55 . This front end searches for an XSL transformation script belonging to the requested XML file and starts the XSL parser 54 with these two files.

Since dynamically generated HTML pages always use the data used from the XML database 50 located locally in the proxy server 1 , the content of this database must be compared with the data available in the devices. This matching process is necessary because a lot of data stored in the XML database 50, such as e.g. B. Measured values are time-varying. The block XML front-end RPC cache 57 takes care of this comparison. When the XSL parser 54 accesses the XML database 50 , the intermediate XML front end 57 checks the validity period of the requested information. If the requested information has already become invalid, the connection manager 52 requests it again from the RPC client 53 from the device, updates it in the XML database 50 and forwards it to the XSL parser 54 .

The device management 49 continuously monitors the status of the devices connected to the device network and updates this information using the XML front-end device data 56 in the XML database 50 .

• - CSS-Stylesheet + XML-Dokument → XML-fähiger Browser
  Der Browser verarbeitet das Dokument und die Darstellungsinformationen in Form eines CSS-Stylesheets und erzeugt eine Präsentation.
• - XSL-Stylesheet + XML-Dokument → XSL-fähiges Darstellungsprogramm
  Ein Darstellungsprogramm, das XSL-Stylesheets verarbeiten kann, erhält neben dem Dokument die Präsentationsinformation in Form eines XSL-Stylesheets.
• - XSL-Stylesheet + XML-Dokument → XSL-Transformator → HTML- Dokument
  Das XML-Dokument wird entsprechend der Transformationsregeln eines XSL-Stylesheets von einem XSL-Transformator in ein (X)HTML-Dokument transformiert, das dann von einem Browser dargestellt werden kann.

The XSL parser 54 is the main link in the display of the current FG1 field devices. , .FGN received data from the XML database 50 . Each XSL script specifies transformation rules which determine the manner in which certain data from the XML database 50 in the form of HTML pages in the user devices N1. , .NN are to be displayed. One of the basic principles of XML is the separation of content and presentation. An XML document only contains "content", its presentation must be defined separately in the form of a style sheet. There are various ways of adding the display information to an XML document. These are based on two basic processes: Either the document is brought into a displayable form according to a style sheet or the style sheet guides the display mechanism in how the individual elements of the document are to be displayed. These two basic processes can be varied in different ways:

• - CSS stylesheet + XML document → XML-capable browser
  The browser processes the document and the presentation information in the form of a CSS style sheet and creates a presentation.
• - XSL stylesheet + XML document → XSL-capable display program
  A display program that can process XSL stylesheets receives the presentation information in the form of an XSL stylesheet in addition to the document.
• - XSL stylesheet + XML document → XSL transformer → HTML document
  The XML document is transformed from an XSL transformer into an (X) HTML document according to the transformation rules of an XSL style sheet, which can then be displayed by a browser.

Fig. 16 shows a schematic block diagram of a XSLT processor (XSL - "Extended Stylesheet Language Transformation").

The block diagram shown in FIG. 16 again illustrates the data flow when an XML file is requested. The file Xview.XML requested by the client is forwarded from the HTTP server to the XSLT processor 54 . This searches for the file Xview.XSL belonging to the requested file Xview.XSL and starts the XSLT processor 54 with these two files. If process data from the XML database 50 of the proxy server is to be used in the transformation process started via the requested file Xview.XML, then the transformation script Xview.XSL must contain a reference to this database. In the example shown in FIG. 16, this XML database 50 has the name Siprogate.XML.

Since all with the help of the user facilities N1. , If the displayed information passes through an XSLT processor when it is requested, it is expedient to check the information requested here for its validity using the XML front end RPC cache 57 and to use the result for an update mechanism. To do this, the XSLT parser must be manipulated so that it can be determined which data from the individual databases are involved in the design of the HTML page to be generated. This information is then used to determine in a second step whether this data is current. Thereupon, the update mechanisms required for this are initiated, if this is necessary, and then the parsing process is started again, whereby only those data are updated that are currently in any form to a user with the help of one or more of the user devices N1. , .NN are displayed. This is achieved by only updating the requested data in the XML database. Due to the possibly considerable overall size of the XML database 50 , this mechanism results in a reduction in the number of field devices FG1. , .FGN and the proxy server 1 transmitted data, because on the one hand only on request and on the other hand only the data required for the respective display are fetched.

Claims (15)

1. Method for transmitting raw data ( 36 ) between a field device ( 33 ) and a user device ( 30 ) for observing and / or operating the field device ( 33 ), the raw data ( 36 ) being held in the field device ( 33 ), a server device ( 34 ) being formed in the field device ( 33 ) and a browser device ( 31 ) being installed on the user device ( 30 ) for data communication with the server device ( 34 ), the method comprising the following method steps: - Forming a communication link for transmitting electronic data between the field device ( 33 ) and the user device ( 30 ); - Transmission of an electronic description page ( 35 ) which can be graphically output on the user device ( 30 ) by means of the browser device ( 31 ) from the server device ( 34 ) of the field device ( 33 ) to the user device ( 30 ) via the communication link, the electronic Description page ( 35 ) comprises at least one electronic reference to the raw data ( 36 ) held in the field device ( 33 ); - Transferring the raw data ( 36 ) from the field device ( 33 ) to the user device ( 30 ); and - Automatic processing of the raw data ( 36 ) in the user device ( 30 ). 2. The method according to claim 1, characterized in that the electronic description page ( 35 ) is automatically analyzed in the user device ( 30 ) after transmission to the user device ( 30 ) in order to record the at least one reference to the raw data ( 36 ), and that the raw data ( 36 ) are automatically transmitted from the field device ( 33 ) to the user device ( 30 ) after the at least one reference has been recorded in the electronic description page ( 35 ). 3. The method according to claim 1, characterized in that one of the at least one reference in the electronic description page ( 35 ) can be assigned electronically by a user using a selection means in the user device ( 30 ) and that the raw data ( 36 ) after The selection of the user is automatically transmitted from the field device ( 33 ) to the user device ( 30 ). 4. The method according to claim 2 or 3, characterized in that the transmission of the raw data ( 36 ) from the field device ( 33 ) to the user device ( 30 ) with the aid of a client process ( 100 ) formed within the browser device ( 31 ). is performed. 5. The method according to claim 4, characterized in that essentially dynamic raw data is transmitted with the aid of the client process ( 100 ) formed within the browser device ( 31 ). 6. The method according to claim 2 or 3, characterized in that the transmission of the raw data ( 36 ) from the field device ( 33 ) to the user device ( 30 ) with the aid of an extension module ("plug-in module") of the browser device ( 31 ) is executed. 7. The method according to claim 6, characterized in that with the aid of the extension module ("plug-in module") of the browser device ( 31 ) substantially static raw data are transmitted. 8. The method according to any one of the preceding claims, characterized in that the electronic description page ( 35 ) is an HTML page. 9. The method according to any one of the preceding claims, characterized in that different electronic protocols are used for transmitting the electronic description page ( 35 ) and for transmitting the raw data ( 36 ). 10. The method according to any one of the preceding claims, characterized in that the browser means (31) analyzes the data transmitted from the field device (33) to the user device (30) raw data (36) and that for processing of the raw data (36) in the User device ( 30 ) an application program is started automatically depending on the result of the analysis of the raw data ( 36 ). 11. Field device with a connection for a communication link ( 2 ) that can be addressed by a client device ( 30 ) via an IP address, a server device ( 34 ) for data communication with a browser device installed on the client device ( 30 ). means (31) through the terminal and storage means (35 a) with a stored herein, electronic Description side (35), wherein the electronic description page (35) comprises an electronic reference to pre-preserved in the field device (33) raw data (36), and wherein the electronic description page ( 35 ), including the raw data ( 36 ) referenced by means of the electronic reference, can be called up electronically via the server device ( 34 ) and the connection. 12. The apparatus according to claim 11, characterized in that the electronic description page ( 35 ) is an HTML page. 13. The apparatus according to claim 11 or 12, characterized in that the server device ( 34 ) is an HTTP server. 14. Device according to one of claims 11 to 13, characterized in that the raw data ( 36 ) comprise measured values and / or event lists. 15. Use of a method according to one of claims 1 to 10 or a device according to one of the claims 11 to 14 for monitoring energy technology systems.